<!DOCTYPE html>
<html>
<head>
	<title>test</title>
	<style type="text/css">
		*{
			padding: 0;
			margin: 0;
		}
		.a{
			width: 1228.8px;
			margin: 47px 153.6px;
			background: red;
			font-size: 0;
		}
		.a div{
			display: inline-block;
			height: 50px;
			width: 245.75px;
		}
		.a1{
			background: green;
			margin-left: 245.75px;
		}
		.a2{background: yellow;}
		.a3{background: black;}
	</style>
</head>
<body>
<div class="a">
	<div class="a1">1</div>
	<div class="a2">2</div>
	<div class="a3">3</div>
</div>
</body>
</html>